PYthon II MAGNUM is a sustained-release, plastic ear tag containing asynergized formulation of zetacypermethrin, a potent, enriched S-isomerpyrethroid compound. This insecticide has excellent activity against many pests,including horn flies that are resistant to certain other insecticides. PYthon IIMAGNUMs larger net weight of 0.54 oz. (15.4 grams) per tag provides greaterinsecticide release for maximum effectiveness against horn flies and otherectoparasites.